Technical Field
The present disclosure relates to an organic light emitting display apparatus and driving method thereof, and more particularly, to an organic light emitting display apparatus and driving method thereof which are capable of compensating a deteriorated image quality caused by leakage current between sub-pixels in which the amount of leakage current varies according to its temperature.
Discussion of the Related Art
As the information age has heightened, display apparatuses for visualizing digital image signals have been rapidly developed. In this regard, research has been continuously conducted on various display apparatuses to develop thin, light weight and low power consumption display apparatuses. Typical examples of such display apparatuses include a plasma display panel (PDP), a field emission display (FED), an electro-wetting display (EWD), a liquid crystal display (LCD) and an organic light emitting display device (OLED).
An organic light emitting display apparatus, which is a self-luminous display device, does not require a separate light source such as a liquid crystal display apparatus, and is therefore made in a light weight and thin form. In addition, the organic light emitting display apparatus is advantageous in terms of low power consumption, wide color gamut, fast response speed, wide viewing angle and infinite contrast ratio. For these reasons, the organic light emitting display apparatus has been regarded as the next generation display.
A pixel area of an organic light emitting display apparatus comprises a plurality of sub-pixels. Each of the sub-pixels comprises an organic light emitting diode (OLED). Each of the organic light emitting diode comprises an anode, an organic emission layer and a cathode.
For the sake of convenience in terms of manufacturing an organic light emitting diode of each sub-pixel, a common layer may be formed over the substantial whole surface by using the open mask technique. For example, at least one common layer is formed to cover the overall pixel area by a whole surface deposition method, which is positioned between an anode and a cathode. Thus, the common layer may act as a leakage current path to the adjacent sub-pixels.
The common layer may be referred as any layer among various layers positioned between an anode and a cathode for improving the performance of the organic light emitting diode. The common layer may be referred as various layers which are configured to cover the overall area of the pixel area and not patterned at each of the sub-pixels. Such common layer may be, for example, an organic layer, a doping layer and/or a conductive layer. Moreover, such common layer may be a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL) and/or an emission layer (EML).
Such common layer may be formed in various ways, and it is not limited to its material, thickness and/or shape. Moreover, such common layer may be referred as any layer positioned between an anode and a cathode and capable of providing a leakage current path to adjacent sub-pixels. In particular, the common layer, capable of allowing the leakage current to flow, may have a conductive characteristic. In addition, the conductivity or resistivity of the common layer may vary according to its temperature. Therefore, the amount of leakage current may vary according to temperature.
The adjacent sub-pixels may be affected by the unwanted leakage current passed through the common layer. Thus, the adjacent sub-pixels may be undesirably emitted by the emitting sub-pixel due to the leakage current. Thus, the contrast ratio may be reduced by the undesired emission. Moreover, the color gamut may be reduced by the leakage current such that the undesired emission provides undesired color contents at the adjacent sub-pixels. Furthermore, the white balance may be shifted. Accordingly, the image quality may be deteriorated.